Bug#1120601: gdk-pixbuf: autopkgtests fail after switching to glycin

[Alessandro Astone]

On 12/11/2025 23:47, Jeremy Bícha wrote:
> Source: gdk-pixbuf
> Version: 2.44.4+dfsg-2
> Severity: serious
> Tags: experimental
> Control: block 1116981 by -1
> X-Debbugs-CC: alessandro.astone at canonical.com
> 
> The autopkgtests fail after switching gdk-pixbuf to use glycin.
> Although using glycin is the upstream default, I believe that
> upstream's CI doesn't run installed tests.
> 
> My initial guess is that maybe the test files are sensitive to what
> software is used to generate the images, but I haven't investigated.
> If this is true, I suggest that the test files should be updated to
> match gdk-pixbuf's defaults even if they fail when not built with
> glycin. This does concern me since glycin and rust-image are still
> under heavy development so maybe these tests would break again for
> future releases.
Actually build-time tests also fail, but we've been accidentally 
ignoring them since 2022...!
https://salsa.debian.org/gnome-team/gdk-pixbuf/-/blob/b6c6b787a0513eb9bdd98a616e772ed6a7513ed9/debian/rules#L84

Upstream CI runs without glycin, which frankly is baffling, so it may 
well just be broken. In facts running "meson test" on an upstream 
checkout with all default build options fails exactly the same way.